Hydraulic artificial hand



May 14, 1946. J. SARGESON HYDRAULIC ARTIFICIAL HAND 2 Sheets-Sheet 1 Filed June 15, 1944 4, 1946. J. SARGESON 2,400,140

HYDRAULIC ARTIFICIAL HAND Filed June 15, 1944 2 Sheets-Sheet 2 Un vew-Tfor J Sargeson Patent ed May 14, 1946 UNITED STATES PATENT OFFICE' HYDRAULIC ARTIFICIAL HAND John Sargeson, Toronto, Ontario, Canada Application June 15, 1944, Serial No. 540,420

9 Claims.

The invention relates to artificial hands in which a hydraulic gripping device is provided for grasping and manipulating tools and other articles.

The invention particularl concerns certain new and useful improvements upon Letters Patent No. 2,182,214, issued to me December 5, 1939.

A general object of the present invention is to produce a more serviceable gripping appliance for an artificial limb and one which is facile of operation. A further object is to provide a gripping appliance in which a hydraulic cylinder has co-acting jaws turnable about the axis thereof and having means by which fluid pressure serves to automatically lock them in selected angular positions to which they may be adjusted as oocasion requires.

A still further object is to furnish a compact and sturdy gripping appliance in which one of the jaws is adjustable outwardly of the fluid cylinder by means of a pair of slide plates, one of which has side edges fitted in guide channels and is notched at a side for locking engagement with a latching device carried by the other slide plate.

A still further object is to produce a gripping appliance in which the fluid cylinder and the jaws ma be encased by means of a removable cover in the configuration of a hand, which is particularly adapted to be worn when the appliance is not in use, and which is so devised that it may be attached in any position to which the adjustable jaw is set. The casing is fashioned with flexed fingers and a thumb. The thumb is slidabl mounted so that it may be adjusted lengthwise of the hand to suit any position of adjustment of the adjustable jaw.

A still further object is to provide a device of the character described having a novel means of actuating a. pump for supplying fluid pressure to the cylinder.

Having recounted the major objects of the invention, subsidiar objects and advantages will be apparent from the ensuing description and drawings in which there is disclosed a selected embodiment of the improved structure.

In the drawings,

Fig. 1 is a longitudinal sectional view of the gripping appliance,

Fig. 2 is a cross section taken on line 2-2 thereof.

Fig. 3 is a cross section on line 3-3 thereof.

Fig. 4 is a side elevation of the gripping appliance showing the casing thereof in section.

Fig. 5 is a cross section on line II of Fig. 4.

Fig. 6 is a further cross section but taken on line 8-6 of that figure.

Fig. 7 is a top plan view of the gripping appliance depicting the casing mounted thereon and broken away in parts to illustrate the construction to better advantage.

Fig. 8 is an elevational view of the pump.

Fig. 9 illustrates a means of strapping the pump on the body of a person so that a shoulder movement may be utilized for operating the fluid cylinder of the gripping appliance.

Fig. 10 is a variant form of attachment means by which the pump may be motivated by a leg movement.

Like numerals of reference indicate corresponding parts in each of the figures throughout the drawings of the invention.

The gripping appliance comprises a hydraulic cylinder ll of a known typehaving a plunger l2 projecting from an end thereof for advancement by liquid under pressure. A standard stuiling box l3 encircles the plunger at the outer end of the cylinder. The inner end of the plunger is formed as a piston and supplied with rings or packing as usual, and the outer end thereof is integral with or secured to a jaw 14 which has a limited travel according to the stroke of the plunger. This movable jaw co-operates with a fixed jaw I5. A length of flexible tubing I6 is connected to the rear of the cylinder for conducting fluid under pressure thereto by which the plunger is advanced for causing the jaws to grasp an object. The plunger is retracted by helical springs I! having their outer ends connected to the movable jaw.

The cylinder is carried by a socket 18 or a comparable element of an artificial limb for attachment to an amputated arm. The cylinder is adjustable to different angular positions as by a swivel connection 18' which may include looking means such as the bolt and nut I9.

The jaws are turnable as a unit aboutthe axis of the cylinder by a ring 20 loosely encircling the cylinder and slidably mounting the rigid jaw. The movable jaw M has an edge portion 2| slidably engaged with the shank 22 of the rigid jaw so that it may not turn independently, as will be best seen from an inspection of Fig. 2.

Novel means are provided to automatically lock the jaws against turning about the cylinder while the plunger is under fluid pressure. The means comprise a circular series of serrations or notches 23 on the outer end of the ring 20 for interfitting engagement with a tooth 24 rigid with the cylintated to an angle best suited for manipulation of a particular tool, and when the movable jaw is advanced into engagement with an object placed between the jaws the outward stress on the rigid jaw urges the ring 20 to slide forwardly so that the tooth 24 will engage the notch nearest to it. Consequently the construction provides for automatically maintaining the jaws in any angular position while the appliance is in use. Once the fluid pressure is released the ring can he slid backwardly to disengage it from the tooth 24. Only a slight axial travel of the ring is required and its movement may be limited by an annulus 25 on the cylinder. Preferably the ring is backed by a spring 26 interposed between the rear end face thereof and the annulus so that it will normally be held in yieldable engagement with the teeth. The coil springs i! are anchored at the rear part of the ring as by lugs 25. These springs coact to retract the plunger when the fluid pressure is removed.

The fixed jaw is adjustable to and away from the movable jaw by a novel structure comprising a slide plate 2'! integral with the ring 20 and fitted in channels or guideways 28 formed in the inner side of the longitudinal shank 22. The shank therefore constitutes a slide plate which can be slid to space the fixed jaw to permit gripping of objects of various sizes within the range of adjustment. One of the side edges of the slide plate 21 is provided with a longitudinal series of suitably spaced notches 29 which are engageable by a spring-pressed latch 30 pivoted at 31 on said shank for locking the fixed jaw in any one of the positions to which it may be set. The latch is disposed at the inner side of the shank and has an arm 32 provided with a button 33 by which it may be depressed to disengage it in making an adjustment.

The shank has a curved outer face 34 extending to the under faces 35' of the guideways 28, The fixed jaw is desirably strengthened by a rib 34' extending from the shank to its distal end.

It will be manifest that the gripping appliance presents a very sturdy and serviceable device by which articles can be grasped firmly and held in a manner best suited for manipulation or for performing a particular task. The cover for encasing the gripping appliance comprises a shell or case 35 representing a hand with the fingers and thumb flexed. The case or shell may be moulded of a suitable plastic or other suitable material and maybe covered with leather or a textile material if desired. It is provided with means by which it may be detachably secured to the rigid jaw. One mode of construction to this end consists of forming the case with a part 36 representing the back of the hand and curved in cross section to flt over the curved face 34 of the shank 22 and to clip thereon as by lips or inward projections 31. The lips or projections may be mouldably produced and adapted to be sprung over the side edges of the shank by flexing the part 36 so that they may engage the faces 35'. At the rear of part 36 and at the end of the finger part 38 there may be similar lips or projections, indicated at 31', for respectively engaging the ends of the shank and the rigid jaw. Said finger part may also have a slot 39 for receiving the rib 34', as shown in Fig. 5. When made of plastic material, the case will possess sufiicient flexibility to enable the cover to be easily applied and removed.

Preferably the thumb 40 is slidable longitudinally of the hand so that its position may be varied to correspond with the positional adjustment of the rigid jaw and also to enable it to be shifted clear of the space between the laws in order that the appliance may be used when the cover is attached. The slidable mounting of the thumb may be achieved in various ways; for instance a slot and pin connection, as at 4|, would provide a satisfactory expedient-see Fig. 'l.

The pump consists of a fluid cylinder 42 having a ram 43 therein projecting from an end thereof with a crossbar 44 to which coil springs 45 are attached. The springs exert pressure on the ram for advancing the movable jaw. The springs normally retain the ram at the inner end of its travel and it therefore follows that the plunger is ordinarily at the outer end of its stroke with the consequence that in order to grasp an object between the jaws it is necessary to withdraw the ram to allow the movable jaw to flrst retract to receive the article and then release the ram so that pressure transmitted by the fluid will exert the gripping force.

The pump is strapped on the body of the wearer and supplied with means by which the ram may be actuated at will, such as :by a shoulder or leg movement. For this purpose the pump is suspended at a side of the chest and rests against a pad, as at 45, of cushioning material fastened thereto in approved manner. The cylinder of the pump is secured to a. shoulder strap 41 which is adjustable and held in place by a cross strap 48 passing around the proximal part of the amputated limb, indicated at 49, and under the other arm. The ram projects from the lower end of the cylinder for operation by the actuating means.

As illustrated in Fig. 9, the means for operating the pump by a shoulder movement comprise a flexible member 50 connected to the ram and to a strap 5| fastened around the leg therebelow at the crotch. The connection with the strap 5i may include a loop 52 which receives a torso strap 53. It may also include an element such as the snap fastener 53' by which the flexible element can be disconnected when it is desired to render the pump inoperative.

When the pump is connected to the operating means it is operable .by raising the shoulder, as indicated in dash lines in Fig. 9, which pulls the pump cylinder upwardly from the tethered ram with the result that an outward movement is imparted to the ram to expel fluid from the cylinder of the gripping appliance. This permits the plunger to retract and the jaw thereon to open. On relaxing the shoulder the springs 45 of the ram urge it to put the fluid under pressure for applying the gripping force on the plunger-jaw.

In the variant form of the operating means shown in Fig. 10, the pump has its ram connected to a strap 54 which in turn is connected to the boot worn on the corresponding side of the body. The connection to the boot is detachable as by a snap fastener 55. The strap is looped to provide a coarse adjustment as by the buckle 56. There may also be a fine adjustment as by a screw device 56'. The lower end of the strap may be secured against the leg by a cross strap 51. In the use of this operating means the strap 54 is adjusted to a taut position while the leg is slightly flexed so that a straightening movement of the leg will exert a pull on this strap to withdraw the ram.

It will be manifest that the invention provides an exceedingly serviceable hydraulic hand. It

will be understood, that such changes and modifications of the invention may be resorted to as come within the spirit and scope of the appended claims.

What I claim is:

1. In a hydraulic artificial hand a pair of cylinders having a fluid coupling, a plunger in one of the cylinders normally held in an advanced position by fluid pressure,'said plunger connected to a gripping element, the other cylinder constituting a pump, a ram therein, a resilient means retaining the ram at the inner end of its stroke for applying pressure upon fluid communicating with the other cylinder by which said plunger is held advanced, means for supporting the pump cylinder, and actuating means for withdrawing the ram topermit the plunger to recede to open the gripping element for receiving an object to be grasped upon subsequent release of the ram.

2. An artificial limb member including a movable element adapted to be attached to a human body, means for actuating said movable element comprising a first cylinder containing an inelastic fluid and adapted to be attached to one part of said body, a resiliently advanced ram in said first cylinder adapted to be attached to another part of said body capable of movement relative to the first mentioned part thereof, the attachment of the cylinder and the ram to said body being devised to utilize said movement to effect withdrawal of the ram, a second cylinder mounted in said artificial limb member, an operative connection between said first cylinder and said second cylinder comprising a conduit containing an inelastic fluid, and a plunger in said second cylinder connected to said movable element of said artificial limb for the actuation thereof.

3. In a hydraulic artificial hand, a jaw supported for opening and closing movements, resilient means urging the jaw to an open position, a pair of fluid cylinders having a fluid coupling, a plunger in one of the cylinders for operating the movable jaw, a ram in the other cylinder for operating the plunger, resilient means retaining the ram at the inner end of its travel, the cylinders containing inelastic fluid and the coupling functioning under pressure of the ram to normal- 1y retain the plunger in an advanced position by which the jaw is held closed, and means for supporting the ram-cylinder and withdrawing the ram to permit the plunger to recede for opening the jaw.

4. In a hydraulic artificial hand, a movable jaw, a pair of fluid cylinders having a fluid coupling, a plunger in one of the cylinders for D- erating the movable jaw, a ram in the other cylinder for operating the plunger, resilient means retaining the ram at the inner end of its travel, the cylinders containing inelastic fluid and the coupling functioning under pressure of the ram to normally retain the plunger in an advanced position by which the jawis held closed, means for strapping the-ram-cylinder on a human body so as to support it for withdrawal of the ram therein, and means for attaching said ram to said body so that a distending movement of the body between the regions of connection of the ramcylinder and the ram serves to withdraw the ram to permit the plunger to recede for opening the jaw.

5. An appliance as defined in claim 4, in which the ram-cylinder is suspended from the shoulder of the wearer, and in which the attachment means for the ram forms a connection with a leg of the body whereby a. distending movement thereof is utilized for actuating the ram.

6. In a hydraulic artificial hand, a pump for operating a gripping appliance, said pump comprising a cylinder having a fluid delivery connection, a ram in the cylinder, resilient means urging the ram to apply pressure upon fluid in the cylinder, means for strapping the cylinder on the person of the wearer, and means for attaching the ram to the person of the wearer so that a distending movement of the person serves to impart a retrograde movement to the ram.

7. In a hydraulic artificial hand, a gripping appliance comprising a rigid jaw, a movable jaw, a cylinder, a plunger therein for advancing the movable jaw in the application of fluid pressure, means by which the jaws are turnable as a unit about the axis of the cylinder to different angular positions, and means including a device by which the jaws are automatically locked against turning when they are brought into grippin contact with an interposed object by advancement of the plunger.

8. In a hydraulic artificial hand, a grippin appliance comprising a cylinder, a fluid plunger reciprocal therein, a movable jaw for operation by the plunger and turnable about its axis, a rigid jaw mounted on the cylinder for turnin about the plunger axis along with the movable jaw to different angular positions, the mounting of the rigid jaw including a member. having a limited sliding movement on the cylinder, and means by which said member is brought into locking engagement with the cylinder to preclude turning of the jaws when the plunger is advanced under fluid pressure.

9. In a hydraulic artificial hand, a gripping appliance comprising a cylinder, a fluid plunger reciprocal therein, a movable jaw for operation by the plunger and turnable about its axis, a rigid law mounted on the cylinder for turning about the plunger axis along with the movable jaw to different angular positions, the mounting of the rigid jaw comprising a ring loosely sleeved on the cylinder and having a limited movement endwise thereof, said ring having a circular series of serrations torwardly disposed, and an element on the cylinder for locking engagement therewith when the rigid jaw is under stress applied by the advancement of the plunger in the grasping of an object.

JOHN SARGESON. 

